After getting a few new bits and parts, I came up with a
much more reliable bumper system... Instead of the
overly-complicated spring/hinge mechanism, I converted it
to a simple stip of
aluminum bent at the ends and near the center. It's simple
and works better! The pics of the bumper are on
the bot's site at
http://www.gear21.com/scook/bot/.

Some of you may have noticed that if it runs into
something in the middle, it won't set off the left or
right switch... but that's why I have the GP2D12 IR range
module *GRIN*.

This week I soldered up the "secondary board" to my OOPic2
so I can attach the 40pin IDE connector to it without
soldering my OOPic board. From the secondary board, I have
8 outputs (enable,fwd,rev, and PWM-speed for left and
right) and 7 inputs (5 contact switches, 1 IR module, and 1
A2D for battery monitoring). BTW, solder flux RULES!

Since the switches are bolted to the outer shell of the
bot, the connections are made to an IDC header, that I can
connect the switches to. That way I can remove the shell
without having permanent wires attached. Using the
internal pullup resistors on the OOPIC is going to make the
switch circuits really simple and clean.

I got a couple emails about the wheels and gear motors. I
bought the motors from www.sciplus.com about 8 months ago.
They were from one of the battery operated kiddy cars. The
output shaft was unique in that it was 2.25" in diameter
and was divided into 10 sections. I was originally going
to just replace the shaft completly, but as luck
would have it, by breaking off every other section, it fit
exactly into my lawn mower wheels. (shell1.jpg
shows the wheel). This was an astounding bit of luck that
it matched size, radius, and depth! After that, I bought
two more motors as spares!

The skeleton is built from aluminum pieces scrounged from
around work (which is why it is almost exactly the same
size as a 12u rack-mount network switch :).

I used "off the shelf" DC motor controllers after many
variations of H-Bridges I built just didn't have the
flexibility I
wanted... For the new controllers, I made a "universal
interface" using cat5 ethernet cable and rj45 connectors,
so I can swap out drive methods (from connected switches,
remote control, to onboard microcontrollers).

Originally I was using a parallel port on a laptop to send
signals to the motor controllers, but the laptop was just
too big, so I got an OOPic a few weeks ago, and have
started using it as the brains...

This week, I'm making an interface to the OOPic so I can
connect 5 contact switches and 1 IR range module for
external sensory duty...